Anyway, Mark Brown (42South) contacted me to ask for more details and then made his own version which he mentioned in his thread on the handbrake recently (http://etypeuk.com/forum/viewtopic.php?t=4130).
He's since been asked for some details so we decided it would be worth putting the details in a new thread in case it is of wider interest. Here's what I did;
The dolly is a piece of 12? x 20? x 1? plywood. The 12? width is just narrow enough to fit between the inner ends of the lower wishbones where they droop down below the bottom plate of the IRS ? any wider and the unit would be balancing on the curved edges of the wishbones ? not good for stability.
I used some 4? plastic swivel castors as wheels which I bought at Machine Mart.
I needed to put some blocks between the castors and the plywood because I needed 7? vertical clearance to get my trolley jack underneath. When making the dolly you need to make sure the clearance is enough to clear the jack chassis when it is slid well under the dolly, not just the lifting saddle if, like mine, the lifting saddle when fully down is actually lower than parts of the chassis of the jack nearer the handle end.
I needed to outrig the two wheels at the rear end of the dolly (the end where the trolley jack has to enter) so I had a full 12? width as the wheels of my trolley jack are about 10? apart and they have to fit between these wheels.
I used a length of angle iron I had lying around to hang the outriggers. I could have left ears on the main plywood sheet to take the outriggers but that would have put the plywood ears under a big bending moment and I preferred to use a good piece of steel to take that bending moment.
I used a single wheel at the front to give a tricycle undercarriage, but with hindsight if I built another one I?d use 4 wheels as it can try to ?nosedive? like a Reliant Robin at the front when maneouvring it around with the IRS onboard.
I didn?t put anything between the plywood and the baseplate of the IRS. You could probably make up some brackets to secure the IRS to the ply but I didn?t find it necessary.
I?ve attached a couple of pics and a sketch ? sorry for the Porsche transaxle spoiling the view which I was too lazy to lift it off for the pics, but you can see the general idea I?m sure.
Mark sensibly made a 4 wheel version and I think he'll post some pics and comments on that one in this thread.